Event Notification Report for May 18, 2006

COLORADO AGREEMENT STATE REPORT - DAMAGED TROXLER GAUGE

The licensee left a paving job site and while driving to another job site noticed that the truck's tailgate was down. The driver stopped and noticed that the gauge was missing and the licensee contacted the State Colorado Department of Health and Environment who responded to incident site. It appears that the gauge was not secured in its casing and most likely was run over on the highway as it fell from the truck bed. Pieces of the gauge (handle and push rod) were found in the proximity of the intersection of Interstate 25 with Academy Boulevard, Colorado Springs, Colorado. The moisture density gauge was a Troxler Model 3401 serial number 30-1031 containing two sources: 8 millicuries of Cs-137 and 40 millicuries of Am/Be. The sources have not yet been found. The State and Highway Patrol are at the incident area and will continue to investigate this occurrence.

At 1155 on 05/18/06, Tim Bonzer from the Colorado Department of Health reported that both sources had been recovered and packed in a sand filled cooler and will be transported to the state office where the sources will be leak checked prior to shipping to Troxler.

THIS MATERIAL EVENT CONTAINS A "LESS THAN CAT 3" LEVEL OF RADIOACTIVE MATERIAL

Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks.

FLORIDA AGREEMENT STATE - DAMAGED TROXLER GAUGE

"Truck belonging to licensee flipped over on interstate, driver is unhurt. Gauge container crushed, gauge handle broken. Licensee performed leak test at scene and transported gauge back to licensed storage facility. Further action is referred to [Florida] Radioactive Materials."

Gauge was a Troxler model number - 3430, serial number 26308. Isotopes - Cs-137, 8 millicuries and Am-241/Be, 40 millicuries. Accident occurred on Interstate 75 at North Bonita Beach Road, Lee County, Florida.

Florida Incident Number: FL06-072

UNEVALUATED FAILURE OF CHARGING PUMP IN FIRE SCENARIO


"On May 18, 2006, it was determined that a previously unevaluated failure mode of charging pumps during a certain 10 CFR 50 Appendix R fire scenarios existed. Charging pumps are credited for specific fire scenarios to be available to make up inventory and provide reactivity control in the reactor coolant system. The engineering evaluation determined that an Appendix R fire scenario could potentially result in the failure of a circuit which would cause the credited charging pump to be tripped and held tripped by the undervoltage protection circuitry. The postulated failure would require diagnosis and manual actions to operate the charging pump.

"A preliminary analysis of the core damage risk associated with this condition was performed, taking into account the frequency of fires in all of the affected areas, the potential failure of fixed and/or manual fire suppression systems, and the required manual operator actions (with assumed failure likelihoods). The results indicate that the additional core damage frequency (CDF) associated with this condition is approximately 1.2E-07/yr.

"Procedures changes to address this issue are being developed."

The NRC Resident Inspector was notified of this event by the licensee.

POSTULATED FLOODING THAT COULD IMPACT BOTH TRAINS OF THE RESIDUAL HEAT REMOVAL (RHR) SYSTEM


"At 1323 the Shift Manger was notified of a flooding concern that could impact both trains of the Residual Heat Removal (RHR) System. At this time both trains of RHR were declared inoperable and actions were taken to isolate the lines that could flood the RHR Pump Pits, The lines in question were from the Spent Fuel Pool Cleanup system specifically associated with the Spent Fuel Pool Dernineralizers and the Pre-filters and Post-filters. These lines were Isolated at 1345. Spent Fuel Pool cooling remained in service following isolation of the Spent Fuel Pool Cleanup system. Both RHR trains were returned to service at 1345.

"Initial piping analysis determined that these lines would have remained intact during and following a seismic event. The final evaluation s expected to be completed within two weeks."

The NRC Resident Inspector was notified of this event by the licensee.